Having PDF pages side-by-side allows you to navigate and compare the content simultaneously. PDF Reader offers Split View mode (Horizontal and Vertical) that allows you to view two documents side-by-side.
1. Open a PDF in PDF Reader app on your Mac
2. Move the pointer to the “View Settings” button in the bottom of the window
3. In Split View section, you could choose Horizontal or Vertical split viewing. Choose either to enable split viewing mode.
4. Select the second PDF from within the secondary viewer (Note: Currently, the secondary viewer only allows you to view the PDF.)
5. Then PDF Reader will display 2 PDFs simultaneously. You can drag the divider to the left or right to adjust the split view.